It follows from the aforesaid that the above-discussed excitonic effects appear due to the crucial change of the dressed Coulomb potential (REF ) for small distances \(r\) , where the dressing field (REF ) induces the repulsive area (see the solid line in Fig. 2a). It should be noted that the inverse physical situation takes place for the repulsive Coulomb interaction. In this case, the circularly polarized field (REF ) induces the attractive area in the core of the repulsive Coulomb potential, which can lead to the electron states bound at various repulsive potentials and, particularly, to the light-induced electron pairing [1]}, [2]}, [3]}, [4]}, [5]}.
